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Malignant Hyperthermia

Malignant Hyperthermia (MH) is a genetic inherited disease which causes a rise in body temp and severe muscle contractions when the person receives certain forms of general anesthesia. Most instances occur in children and has been estimated to be present in about one case per 15000 surgeries. It is less frequent in adults.

MH is a dominant trait. This means that only one parent has to have the disease to pass it on to their child. It may also be associated with other musculoskeletal diseases. There is usually a history of an MH episode or an unexplained death as a result of anesthesia in a patient’s family history. In case of a non specific history or a history of high body temperature after general anesthesia a muscle biopsy may be obtained to confirm the diagnosis.

The signs of Malignant Hyperthermia attacks are generally rapid onset in nature and occur within the first hour of anesthesia. There is a rapid rise in body temperature up to 113 degrees. There is also a rise in heart rate, respiratory rate and blood pressure. There is onset of muscle contraction or rigidity. There is also the possibility of dark brown urine formation.

Treating MH is geared toward reducing body temperature and ceasing the cascade. All triggering agents are immediately stopped and respiratory rate is increased with the administration of oxygen to remove excess CO2 from the system. Packing the patient in ice as well as irrigating the stomach and bladder with cold solution are important. Maintaining intravenous fluids is also crucial to avoid kidney damage. The key drug to administer is dantrolene which has significantly improved the outcome of MH. This drug relaxes the muscles and stops the contractions.

Malignant Hyperthermia can lead to respiratory or cardiac arrest, brain damage, or organ failure. When the disease was first diagnosed nearly 50 years ago it was associated with a survival of only 20%. Today, due to earlier diagnosis and dantrolene treatment there is a survival of greater than 90%.

Anesthesiologists can prevent the onset of MH by avoiding its triggers. These triggers include a paralytic (paralyzing) agent called succinylcholine and inhalational agents (gases) during general anesthesia. General anesthesia can be performed safely in the MH individual if precautions are taken.

MH, as well as all disease processes, are taken very seriously at my surgical center. In patients who have had uneventful general anesthesia in the past we are able to perform traditional anesthesia. In those patients who have not had anesthesia in the past we perform an intravenous anesthesia only. This also holds true for anyone with a questionable history. In these situations intravenous anesthesia only is administered.

For more information about Malignant Hyperthermia there is a hotline: 1-(800)-644-9737
Or you can visit MH Muscle Biopsy Centers